LTC4085 - USB Power Manager with Ideal Diode Controller and Li-Ion Charger
Features
- Seamless Transition Between Input Power Sources: Li-Ion Battery, USB and 5V Wall Adapter
- 215mΩ Internal Ideal Diode Plus Optional External Ideal Diode Controller Provide Low Loss PowerPathTM When Wall Adapter/USB Input Not Present
- Load Dependent Charging Guarantees Accurate USB Input Current Compliance
- Constant-Current/Constant-Voltage Operation with Thermal Feedback to Maximize Charging Rate Without Risk of Overheating
- Selectable 100% or 20% Input Current Limit (e.g., 500mA/100mA)
- Battery Charge Current Independently Programmable Up to 1.2A
- Preset 4.2V Charge Voltage with 0.8% Accuracy
- C/10 Charge Current Detection Output
- NTC Thermistor Input for Temperature Qualified Charging
- Tiny (4mm × 3mm × 0.75mm) 14-Lead DFN Package
Typical Application
Description
The LTC4085 is a USB power manager and Li-Ion battery charger designed for portable battery-powered applications. The part controls the total current used by the USB peripheral for operation and battery charging. The total input current can be limited to 20% or 100% of a programmed value up to 1.5A (typically 100mA or 500mA). Battery charge current is automatically reduced such that the sum of the load current and charge current does not exceed the programmed input current limit.
The LTC4085 includes a complete constant-current/constant- voltage linear charger for single cell Li-ion batteries. The float voltage applied to the battery is held to a tight 0.8% tolerance, and charge current is programmable using an external resistor to ground. An end-of-charge status output CHRG indicates full charge. Total charge time is programmable by an external capacitor to ground. When the battery drops 100mV below the float voltage, automatic recharging of the battery occurs. Also featured is an NTC thermistor input used to monitor battery temperature while charging.
The LTC4085 is available in a 14-lead low profile 4mm × 3mm DFN package.
| Float Voltage (V) | NTC Hot Threshold | Undervoltage Current Limit | |
|---|---|---|---|
| LTC4085 | 4.2V | 29% Vvntc | Yes |
| LTC4085-1 | 4.1V | 32.6% Vvntc | Yes |
| LTC4085-3 | 3.95V | 32.6% Vvntc | Yes |
| LTC4085-4 | 3.95V | 32.6% Vvntc | No |
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LTC4085EDE#PBF | 4x3 DFN-14 | DE | E | 05-08-1708 | Yes |
| LTC4085EDE#TRPBF | 4x3 DFN-14 | DE | E | 05-08-1708 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC4085EDE#PBF | 4x3 DFN-14 | E | $2.36 | $1.65 | Yes | |
| LTC4085EDE#TRPBF | 4x3 DFN-14 | E | $1.71 | Yes | ||
| Buy Now • Request Samples | ||||||
Demo Boards
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC937A | LTC4085EDE Demo Board | 700mA CC/CV Li-Ion Linear Charger, VIN = 4.5V to 5.5V | $150.00 | |
| Buy Now | |||
Applications
- Portable USB Devices: Cameras, MP3 Players, PDAs
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Design Tools
LTspice
LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice
Models for the following parts are available in LTspice:
LTC4085
LTC4085-1
LTC4085-3
LTC4085-4
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
